Early full weight-bearing and gait exercise after cemented total ankle arthroplasty with a modified anterolateral approach

ABSTRACT

Objectives

According to the conventional postoperative procedure after total ankle arthroplasty (TAA), mobilization and weight-bearing is currently started after completion of wound healing. Recently, early mobilization for dorsiflexion after TAA with modified antero-lateral approach was reported to be feasible and safe. To investigate the further possibility of expediting rehabilitation, this study evaluated the feasibility and safety of early full weight-bearing and gait exercise after cemented TAA.

Materials and Methods

This retrospective, observational study investigated 23 consecutive ankles (OA: 14 ankles, RA: 9 ankles) that had received cemented TAA with a modified antero-lateral approach. These ankles were divided into three groups 1. conventional postoperative protocol, 2. early dorsiflexion protocol, 3. early dorsiflexion+full weight-bearing protocol. Postoperative wound complications were observed and recorded. Number of days for hospitalization was also evaluated.

Results

No postoperative complications related to wound healing were observed even after early full weight-bearing and gait exercise. Days for hospitalization was significantly shortened in early full weight-bearing and gait exercise group (group 3) from 35-38 days to 24 days.

Conclusions

Within this small number of cases, early full weight-bearing and gait exercise from 7 days after cemented TAA was feasible and safe with the modified antero-lateral approach. Combination of early dorsiflexion mobilization and weight-bearing/gait exercise contributed to shortening the hospitalization day. Innovations in postoperative procedures for rehabilitation after TAA can be expected.

Introduction

Various postoperative protocols for rehabilitation have been applied, and several guidelines for rehabilitation after total ankle arthroplasty (TAA) have been established [1–3]. None of the present guidelines have described mobilization in the early phase after surgery. Ankle mobilization according to existing protocols is currently started at least 2–3 weeks postoperatively. Resting, immobilization, and non-weight-bearing have been recommended for 0–2 weeks after surgery to allow wound healing [1–3]. During this period, mobilization is allowed only for the toes. On the other hand, early (about 24 h after surgery) knee-bending exercise has increasingly been adopted after total knee arthroplasty [4]. This difference in early-phase postoperative procedures between total knee arthroplasty and TAA is due to the prioritization of wound healing. To resolve such an issue, a modified anterolateral approach has recently been introduced in which the skin incision is not placed directly above the tibialis anterior (TA)/extensor halluces longs tendon and the retinaculum around the TA tendon is not opened [5, 6]. Utilizing this approach allows stable wound healing and thus reduces the number of days until suture removal [5]. Furthermore, it was recently confirmed that early mobilization of dorsiflexion from 3 days after cemented TAA was feasible and safe [6]. However, protocols for weight-bearing and gait exercise were not changed in the study. This study thus evaluated the feasibility and safety of early full weight-bearing and gait exercise 7 days after TAA under the condition that both tibial and talar components were implanted with bone cement.

Materials and methods

This retrospective, observational study investigated 23 patients with 23 consecutive ankles [osteoarthritis: 14 ankles, rheumatoid arthritis (RA): 9 ankles] in single institution that had received a mobile-bearing ankle prosthesis (FINE mobile-bearing prosthesis; Teijin-Nakashima Medical Co., Okayama, Japan) [7–9] for treatment of end-stage ankle deformity/destruction from November 2019 to August 2022. All 23 ankles underwent treatment using a modified anterolateral approach and were divided into three groups: (1) conventional postoperative protocol: eight ankles (November 2019–May 2020), (2) early dorsiflexion protocol: seven ankles (December 2019–October 2021), and (3) early dorsiflexion + full weight-bearing protocol: eight ankles (December 2021–August 2022), using historical control. In Group 1, both range of motion (ROM) exercise and weight-bearing were started after suture removal (about 2–3 weeks after surgery). In Group 2, passive/active dorsiflexion exercise was started from 3 days after surgery. In Group 3, after early dorsiflexion mobilization (3 days), full weight-bearing and gait exercise were started from 7 days after surgery (10 days after if malleolar osteotomy was added).The demographic characteristics of patients are shown in Table 1. This research was performed in compliance with the Declaration of Helsinki and was approved by the institutional review boards of the institutions affiliated with the authors. Written informed consent was obtained from all patients.

Surgical technique

Modified anterolateral approach

The modified anterolateral approach was performed as described previously [5, 6]. The skin incision was based on the conventional anterolateral approach/Böhler’s incision [10]. The incision was made one finger width (1.5–2.0 cm) laterally from the extensor halluces longs, and then, the superficial peroneal nerve was identified and retracted. The medial side of the stem of the inferior extensor retinaculum was opened without intervention to the superior and inferior subdivisions of the superomedial band of the inferior extensor retinaculum, which forms a tunnel for the TA tendon [5, 6]. The extensor digitorum longus was then retracted laterally, and the TA/extensor halluces longs compartment was retracted medially. The approach to fat tissue was continued, and then, the dorsalis pedis artery/vein and deep peroneal nerve were retracted medially or laterally. If these neurovascular bundles shifted laterally, lateral retract would be easy for the approach; however, if the branch artery to medial malleolus could be preserved, medial retract of the bundle would be recommended in order to maintain the blood supply to medial malleolus and talus. The exposed superficial peroneal nerve was gently retracted [5, 6].

TAA and postoperative procedures

Surgery was performed as described previously using a mobile-bearing ankle prosthesis design (FINE mobile-bearing prosthesis; Teijin-Nakashima Medical Co.) [7]. After preparation for tibia/talus implantation, medial malleolar lengthening osteotomy (preserving the periosteum) was added if the tightness of soft tissues was not acceptable [2, 5]. Both tibial and talar components were implanted with bone cement. Routine wound closure was completed with careful suturing of the ankle joint capsule and extensor retinaculum. The subcutaneous layer was sutured as much as possible with 3–0 absorbable thread. The skin layer was sutured with 4–0 Nylon vertical mattress sutures. Intraoperative events and/or optional procedure are described in Table 2.

In Group 1: conventional postoperative protocol, the ankle was placed gently under the support of soft splint fixation. Patients were prohibited from dorsiflexion/plantar flexion within 3 days after surgery, but calf massages and toe motion exercises were started at 1 day after surgery. In Group 2: early dorsiflexion protocol, after 3 days postoperatively, both active and passive ROM exercises for dorsiflexion were started. In Group 3: early dorsiflexion + full weight-bearing protocol, both active and passive ROM exercises for dorsiflexion were started at 3 days after surgery, full weight-bearing and gait exercise were started after 7 days postoperatively. If malleolar osteotomy was added as in malleolar fracture cases, the exercise was started 10 days after surgery with an attached ankle brace to avoid ankle sprains [7]. Plantar flexion exercise (passive and active) was started at 10 days after surgery.

Clinical assessments

The number of days to suture removal after TAA was recorded. Suture removal after TAA was planned for around 2 weeks after TAA with careful observation of the wound state. Occurrences of postoperative events such as blister formation, eschar formation (width >10 mm) on the wound, and wound dehiscence were observed and recorded. Decreased peri-incisional sensation was checked, since the superficial peroneal nerve had been retracted intraoperatively. These investigations were based on the evaluation previously described [5, 6]. As a criterion for suture removal, confirmation that there is no exudate from the wound and that there is no wound dehiscence even if tension to both sides of the wound was applied was required.

The ROM of dorsiflexion/plantar flexion was also measured preoperatively and at final follow-up. ROM measurement was based on the methods in the previous reports [11, 12]. Days for hospitalization were also counted and compared between the three groups. Because there are differences of the instructions/guidelines for hospitalization days between each hospital, ankles in single institution were evaluated in this study. As a criterion for hospital discharge, patient should be able to walk on flat ground alone or with a T-cane, furthermore be able to go up and down stairs alone or holding a handrail.

For cases of RA, disease activity was assessed using the disease activity score of 28 joints, C-reactive protein score [13]. As clinical assessments, patients completed a self-administered foot evaluation questionnaire (SAFE-Q) [14] and the Japanese Society for Surgery of the Foot (JSSF) ankle/hindfoot score (based on the American Orthopaedic Foot and Ankle Society score modifications for the Japanese population) [15, 16] preoperatively and at final follow-up.

Statistical analysis

All data are expressed as mean ± standard deviation. The differences in the measured (continuous) variables between the three groups were determined by analysis of variance, and the differences between preoperative and postoperative data were assessed by a paired Wilcoxon signed-rank test. Concerning categorical variables, Chi-square test was used to test between the three groups (P < .05). JMP version 13 statistical analysis software (SAS Institute Inc., Cary, NC, USA) was used. Values of P < .05 were considered significant.

Results

Intraoperative and postoperative events involving the wound site during wound healing.

There is no significant change in intraoperative events between each group (Table 2).

No blister or eschar formation (width >10 mm) was seen even after mobilization (Table 3). No wound dehiscence was identified after suture removal. There was no evidence of deep infection (Table 3; Figure 1). Fortunately, no peri-incisional decrease in sensation was seen in any cases (Table 3).

Number of days to suture removal

The mean number of days to suture removal in conventional group was 19.1 days. In early rehabilitation groups, it was shortened to 14.1 days in Group 2 and to 12.8 days in Group 3. After removal, no wound dehiscence was seen even after early mobilization for dorsiflexion, early full weight-bearing, and gait exercise (both Groups 2 and 3) (Table 3).

Ankle ROM

In conventional group, ROM for both dorsiflexion and plantar flexion showed no significant improvement after surgery. In Group 2, ROM for dorsiflexion was significantly increased after surgery (from 9° to 16°), whereas plantar flexion showed only a non-significant tendency toward increasing after surgery (from 31° to 39°) (Table 4). On the other hand, in Group 3, ROM for both dorsiflexion and plantar flexion showed significant improvement after surgery (dorsiflexion: from 5° to 16° and plantar flexion: from 28° to 39°).

Days for hospitalization

In early full weight-bearing and gait exercise group (Group 3), days for hospitalization were significantly shortened (24.1 days); however, early dorsiflexion ROM group (Group 2) showed no significant shortening of the days (35.9 days) as compared with the conventional protocol group (37.6 days) (Table 3).

Clinical assessment

Generally, significant improvements in each score for the SAFE-Q and JSSF ankle/hindfoot were seen after surgery; however, some indices in SAFE-Q scale (General health and well-being and Shoe-related) showed no significant improvement in the conventional rehabilitation group (Group 1). In early rehabilitation groups (Groups 2 and 3), all indices of SAFE-Q scale showed significant improvement.

Discussion

This study revealed that early full weight-bearing and gait exercise after cemented TAA utilizing a modified anterolateral approach were feasible and safe. Furthermore, early mobilization, weight-bearing, and gait exercise had a possibility to contribute to shortening the hospitalization days. When tibial and talar components were implanted with bone cement, primary fixation would be sufficiently rigid. The mechanics of the bone-implant boundary thus do not appear to be affected when mobilization is restarted. In this study, mobilization was started 3 days after surgery in all ankles, but the surgical site was under conditions of coagulation and the inflammation phase of the wound-healing process within 3 days after surgery [17]. Thus, to prevent a high-pressure state in the subcutaneous compartment during the first 3 days after surgery, rest (immobilization), ice, compression, and elevation treatment was prioritized over mobilization. Drainage should also be performed if continuous oozing is seen at skin closure. Fortunately, no discharge from the wound was seen throughout the period after resuming mobilization and weight-bearing (Table 3). Furthermore, no wound dehiscence was seen after suture removal (Table 3). From these observations, even if wound healing has not been completed, early mobilization for dorsiflexion, full weight-bearing, and gait exercise appears feasible and safe as long as the modified anterolateral approach is utilized for TAA.

Focusing on dorsiflexion mobilization from the early phase after TAA is important from the perspective of improving foot/ankle function and kinematics [18–24] and preventing deep venous thrombosis [25, 26]. Next, focusing on full weight-bearing and gait exercise from early phase is also important from the perspective of preventing the prolonged bedrest-induced osteopenia, disuse muscle atrophy, weakness, and subsequent decreasing of physical mobility [27–33]. Specifically, these issues should be avoided in elderly patients. As well known, since hospitalization affects the physical function and mobility, especially in older people [34], hospitalization day should be shortened as much as possible. Such consideration should be carried out for RA patients, in the perspective of preventing the secondary muscle weakness and sarcopenia [35, 36]. In this study, both early mobilization and weight-bearing/gait exercise could contribute to shortening the days for hospitalization, while early mobilization alone could not contribute (Table 3), suggesting the importance of weight-bearing from early phase after TAA, not mobilization alone in order to prevent the disuse-induced decline of physical mobility. Furthermore, ROM for plantar flexion of ankle was also significantly increased, and the clinical score (SAFE-Q) also improved with a stronger significant difference in the early weight-bearing group (Table 4), also suggesting the importance of early weight-bearing. Improvement in both dorsiflexion and plantar flexion might contribute to increasing the patient satisfaction. Taken together, the modified anterolateral approach for TAA is considered to be useful for early starting of dorsiflexion and full weight-bearing, contributing to shortening the hospitalization days, increasing ROM for both dorsiflexion and plantar flexion, and more significant improving of clinical condition, and subsequently could have a possibility to reduce the disuse/unloading-induced decline of physical mobility.

Some limitations to this study need to be kept in mind. First, plantar flexion exercise was not started from the early phase in this study. The anterior soft tissues, including the anterior capsule, extensor retinaculum, and skin, are stretched during plantar flexion of the ankle joint [1, 5], so plantar flexion exercises were deliberately not introduced to avoid wound dehiscence. In the near future, the timing of mobilization for plantar flexion should also be discussed. Indeed, marginally significant improvement of plantar flexion was observed (P = .046) even in both early mobilization and weight-bearing groups in this study (Table 4), so mobilization of plantar flexion should be further discussed. Second, whether early mobilization could be started even in cases of non-cemented TAA remains unclear. As a biological interface between bone and the implant surface is required for non-cemented TAA, early mobilization during the period before primary fixation is sufficient might adversely affect bone-implant fixation. Third, to further expedite rehabilitation, initiating full weight-bearing and gait exercises at the earliest need to be discussed. As described previously, substantial skeletal muscle loss occurs during only 5 days of disuse [37], and it is considered desirable to start full weight-bearing and gait exercise earlier than 7 days after surgery as in this study. Fourth, the evaluations mentioned earlier should be discussed based on the accumulation of more cases in the future. Fifth, although there was no significant difference, it should also be considered that the small number of RA cases, relatively shorter disease duration, and lower disease activity may have influenced the results especially in Group 3. Sixth, the three groups in this study were not grouped by random allocation but historical control; furthermore, surgeries were not performed by a single surgeon but two surgeons (T.N. and M.H.). These issues are also the limitations of this study. Seventh, although the number of days to suture removal and hospitalization were based on certain criteria described in the manuscript, these judgements were not performed by a single surgeon. These points are also the limitation of this study.

In conclusion, within this small number of cases, early full weight-bearing and gait exercise from 7 days after cemented TAA were feasible and safe with the modified anterolateral approach. Combination of early dorsiflexion mobilization and full weight-bearing/gait exercise contributed to shortening the hospitalization days and improving ROM for both dorsiflexion and plantar flexion after surgery. Innovations in postoperative procedures for rehabilitation after TAA can be expected.

Acknowledgements

The authors would like to express their profound gratitude to all the medical assistants, physical therapists, and rheumatologists of National Hospital Organization, for their excellent support.

Conflict of interest

None declared.

Funding

This work did not receive any grants from funding agencies in the public, commercial, or not-for-profit sectors.

None of the authors have any commercial or financial involvements in connection with this study.

Ethical approval

Ethical approval for this study was obtained from the Institutional Review Board of National Hospital Organization, Osaka Minami Medical Center (approval number: R4-28).

References